Door back for a safe



FIG. 1 is a left front perspective view of a door back for a safe showing my design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The portions of the drawings shown in broken lines represent environmental structure and form no part of the claimed design. 

The ornamental design for a door back for a safe, as shown and described. 